Process and composition of matter for increasing the fluidity of molten metal



Aug. 24, 1926. 1,596,888

A. PACZ PROCESS AND COMPOSI N OF MATTER FOR INCREASING THE FLUID OF MOLTEN METAL FiledNov. '7, 1922 v INVENTOR. Amdu-r Pucz Y ATTORNEY. 1

Patented Aug. 24, 1926.

UNITED STATES ALADAR PACZ, OF EAST CLEVELAND, OHIO.

PROCESS AN D COMFOSI'IION'OF HATTER FOR INCREASING THE FLUIDITY OF MOL'IEN METAL. 1

Application filed November 7, 1922. Serial No. 589,501.

This invention relates to the preparation and casting of metals and alloys and has for its object the improvement of the metals in point of fluidity whereby the casting is 5 facilitated and of physical properties whereby the resulting article is rendered more valuable. For example in the casting of iron and steel itsometimes happens that the metal becomes unduly cool before the pouring is completed, in technical language it becomes dull. This may occur by reason of delays in pouring the metal from the ladies or may occur in the ouring basins or risers of the molds themse ves, particularly 1 where the molds are large anda considerable uantity of metal is required to compensate or the cooling shrinka e which always occurs prior to solidification. One object of my invention is the provision of means to secure alocal heating of the metal if and when required and this not only without injuring the properties of the metal but with a positive-benefit thereto; other objects are the provision of these means in a convenient and inexpensive form; the provision of means for producing alloys of the kind described in small quantities and without special preparations even where the heating efle ct is not required; while further objects and advantages of my invention will become apparent as this description proceeds.

The essence of my invention consists in producing inside the molten metal an exothermic chemical reaction whose products melt at such a temperature as not to detract from the fluidity. In practice I preferably utilize the alumino-thermic reaction wherein the heat is generated by the reaction of metallic aluminum on the oxides of metals which are reduced thereby under the surrounding temperature conditions; and I incorporate with this mixture a metal or compound of a metal of such nature as will reduce the melting point of the resulting product to whatever degree may be desired, or will have the desired effect upon its physical properties.

For example in connection with the casting of iron or steel in ordinary foundry practice the alumino-thermic reaction above mentioned is best obtained by inserting into the ladle or pouring basin or riser an iron can containing a mixture of iron oxide and aluminum wder in the desired proportions, toget or with an igniting charge, in

case the temperature of the metal be not great enou h to start the reaction. If these materials a one be used, the resulting product, being almost pure iron, will have a very high melting point which will lar ely offset the advantages of the heat evolv Therefore I add to this can orcharge a metal or metal-compound which will combine with this liberated iron to reduce its meltin point. This substance can be either a metai' or an alloy, or a compound which will be reduced to metallic form as a part of the reaction. I prefer boric' anhydride forthis purpose because this is reduced by the alummum with evolution of heat and the liberated boron unites with the liberated iron producing an alloy of remarkably high tensile strength and percentage elongation and of remarkably low melting point. Thus thetensile strength of an alloy of iron with 3 per cent of boron and less than per cent of carbon exceeds'50,000 pounds per square inch and its meltin point approximates that of cast iron. maller proportions of boron produce smaller depressions of the melting point but assist to that extent in connection with cast iron and conform more closely to the conditions encountered in casting steel.

It is not necessary that the'boron be added in the oxide form as it can also be used in the previously alloyed condition, for example ferro-boron powdered and incorporated with the mixture. This modification of the procedure is entirely operative but I consider it slightly less advantageous practically for the reason that the ferroboron is more expensive than the boracic anhydride and the melting of the same abstracts a part of the heat produced by the reaction while the reduction of the boracic anhydride adds heat to the reaction.

Also this invention is not confined to boron alone since any other substance can be employed which will lower the melting point of iron, for example manganese, which, as before, can be used either in the oxide form or as term-manganese. However, boron appears to have a larger depressing efiect on the melting point of iron than any other material outside of carbon. I

This process is not restricted to situations wherein the main consideration is the evolution of heat, but it may be used where a modification of the metal itself is desired.

phglsi'cal properties.

. side of the weld, add

pro rties. h ither is this. with an alumino-t invention is also advantageous in cases wherein the alumino-theimm reaction is employed for welding parts together, In order to secure a better corres ondence between the melting point and ysical properties'of the original metal. hus when two cast iron parts are attempted to be welded together by the use of a mixture of 1ron oxide and aluminum powder, the solidifying point of the pure iron produced by the reaction is some 300 above the melting\ point of the cast iron to be welded, whic 15 vs likely to result in a to which the physical properties of the pure iron difi'er iii'gatly from those of the cast iron. I have covered that by mixing the alumino-thermic ingredients with boron in 'a reacting condition as hereinbefore described, the welding operation is facilitated because of the close correspondence in melting points and-the ultimate strength of the'work is increased because of the close agreement in physical process restricted to use ermic mixture uponv an iron base but may be used to advantage with iron-free materials. Thus in the manufac-. ture of stellite consisting of cobalt, chromium and tungsten or molybdenum, or of nichrome containing only nickel and chromium, or of Monel metal consisting of nickel and copper, I find it advantageous to use an alumino-thermic mixture based upon one of the ingredients of the alloy in question together with a proportion of boron either elemental or in a reacting condition, which has the same effect in reducing the melting point as in the case of 1ron and apare to have no injurious chemical action. I: such cases the can is made of a metal which will not injure the bath. In the preparation of this mixture it is important to use water-free ingredients and while this can be done in many waysI prefer when using boracic anhydride to heat it with the iron oxide thereby simultaneousl driving off the water of crystallization, an

mixing the ingredients closely together. This produces in e fiecta very brittle glass which is easily lpowdered and mixed with the powdered a uminum. The amount of boron or other ingredients employed deoor contact at eac masses pends upon the purpose and upon the composition of the surrounding substances. Thus for use with cast iron I refer to use an amount of boracic anhydri e as will afford an amount of boron equal to about three percent of the iron content of the iron oxide, since this affords a eutectic of minimum meltin point and very high strength. For use wit steel one can use less boron since reduction in meltin point is not so important, but at least a out A) of 1 percent is good practice since even this small amount has a material effect in improving the physical pro erties of the reduced iron. In case it be esired to mix the boron throughout the, mass of the surroundin metal a larger proportion should be used: although large improvements in physical properties of steel, and especially such alloy steels as those of nickel or chromium, are obtained with as little boron as 1 9' rcent of thewhole. It is used in approximately. 7

the same proportion in company with nicke chromium, etc. 7

In the drawings acompanyin and forming a part of this apfilication Ihave illustrated diagrammatica y certain of the uses of my invention and the steps in its performance. In this drawing Fig. 1 is a sectional view of a ladle showing the mode of treating the same when the metal becomes chilled or dull; Fig. 2 is a view of a simlecan or package ofmy improved material;

' ig. 3 illustrates the mode of making alloy steel in an ingot mold by the use of my improvements; Fig. 4 illustrates the mode of employing my invention for keepin the metal liquid in a mold riser; and ig. 5 illustrates one mode of emplo ing my invention in connection with wel ing two parts together.

In Fig. 1, 1 represents the body of a ladle which may be of any suitable size, and 2 .the metal support by which it is carried. 3 represents the molten metal inside the ladle, 4 a metal container (preferably of the same composition as the predominant metal in the ladle) and containing my improved mixture, and 5 represents a metal rod by means of which the container is introduced into the molten bath and held there until the reaction is complete or at least well started. For example, in connection with the casting of iron, the rod is made of steel or wrought iron, and the container 4 is a sheet iron can.

In F 9 the bottom of an ingot mold filled with molten metal 10, and 11 represents the canister of ingredients which is introduced and held down by the rod 12. When the metal is steel, this rod is usually melted ofi durin the reaction.

n Fig. 4, 14 represents the cope, 15 the dra and 16 the ase-board of a common san -mold whose parts are represented at ig. 3, 8 represents the side wall and 17-17. .18 represents the sprue or riser which is hollowed out at theupper end to form a pouring basin of suflicient size to hold a considerable amount of molten metal 19. 20 represents a small can of my improved material means of a rod 21 for the purpose of heating this metal locally, and keeping the same fluid so .it can flow into the mold as the It Wlll be understood that my invention comprehends the introduction of my temperature modifying material into the reacting mixture, regardless as to whether the reaction itself is to occur inside of-a molten body of metal as shown in Figs. 1, 3. and 4 or in a separate container which is discharged into the point of use as in Fig. 5; and also regardless whether it is employed for reheating uniformly a mass of metal as in Fig. '1, or heating locally a portion of the mass of metal as in Fig. 4, or modifying the characteristics of a mass of metal regardless of the heating efiect as in Fig. 3, or for any other purpose to which the same may be applicable. It will also be understood ,that whereas it is best to employ such an amount of the added material as will cause the melting point of the evolved metal to conform closely to that of the metal with which it'is used, whether the same be already molten as shown in Fig. 4 oralready solid as shown in Fig. 5, I do not limit myself thereto since some benefit is obtained by even smaller depressions of the melting point, and certain advantages are also obtainable by over-depression of the melting point. Accordingly 1 limit myself in no wise except as recited in the claiins hereto annexed or required by the prior s'tate of the art.

Having ,thus described my invention, what I claim is:

1. A composition of matter for the purpose described containing powdered alumiintroduced therein by .num, an oxygen compound ofboron, and the oxide of a metal which is reduced by aluminum and which also alloys with boron. 2. A composition of matter for the purpose described containing powdered aluminum, the oxide of one or more metals capable of being reduced by aluminum, and boracic anhydride.

3. A. composition of matter for the purpose described containing powdered aluminum mixed with the oxides of iron and boron. 1

4. A composition of matter for. the purpose described containing powdered aluminum, an oxide of a metal which is reduced by aluminum and a compoundv of boron containing an amount of boron amounting to between about percent and 4 percent of that of the metal to be reduced.

5. The process of increasing the fluidity of molten metal which consists in introducing therein a mixture of aluminum powder and an oxide of the first mentioned metal, together with the oxide of boron to form a eutectic therewith. v

6. In the art of casting, the improvement which consists in increasing the fluidity of the metal in the pouring basin by introducing therein a mixture of the oxide of that metal with boracic anhydride and enough powdered aluminum to reduce both oxides.

7. The process of improving the properties of ferrous metal which consists of introducing into the same when molten a mixture of powdered aluminum and the oxide of such metal together with oxide of boron.

8-. The process of reviving of dull melts of ferrous metal which consists of introducing therein an intimate mixture containing powdered aluminum and an oxide of a metal which is reduced by aluminum, and

a compound of boron in a reacting condition, whereby the heat evolve-d may increase the temperatureand the eutectic iron-boron alloy may increase the fluidity.

9. The process of producing ferrous metal signature.

ALADAR PACZ. 

